The present invention is concerned with an electric connector whose construction obviates electrocution accidents.
Safety arrangements suitable for connectors of known type are known. A well-known safety arrangement is constituted by a disc carrying two pins of insulating plastics material and formed when a socket is not in use, the insulating pins of the disc are engaged in the holes of the socket. This system permits isolation of a socket and protection against the risks of electrocution, especially for children.
This safety arrangement (which can equally be used with three phase, the disc having three pins) has inconveniences. The main one is that it can only be put in place when the socket is not in use. Moreover, the plastic pins frequently break inside the socket and thus it is necessary to replace same.
It is known that practically all industrial machines and, increasingly, a number of important domestic appliances must be earthed. In an installation, domestic or industrial, all the earths of machines are connected together and to a wire which is theoretically put into the ground. In practice, there is frequently a fault in the power supply system. For example, the earth of a machine is not connected to the earth pin of the connector. It may happen also that all the earths of the electric machines of an installation may be correctly connected together and branched to the earth wire of the power supply network; but said wire is not connected to earth.
In these conditions, it is evident that the electric installation is no longer safe in the case of a short circuit. Indeed, when a machine is badly insulated, the earth wire whose electric resistance is lower than that of the user shunts the short-circuit current. If the connection between the ground and the earth of the machine is not assured, the current passes to the user with risk of electrocution.